ABSTRACT Strategies for conserving natural resources and reducing agricultural inputs are the great challenge for agriculture, such as sustainable alternatives to control agricultural pests of high economic impact, e.g. plant-parasitic nematodes. This work aimed to evaluate phytonematode’s population dynamics in common bean cultivation grown under crop rotations and no-tillage system. The maize was seeded under pearl millet straw and intercropped with three different crops systems: i) exclusive maize system, ii) maize intercropped with brachiaria and, iii) maize intercropped with crotalaria. The experimental design was a randomized complete block with three treatments (crops systems) and 4 blocks (5 subsamples each block). The common bean was seeded on the straw of exclusive or intercropped maize. The phytonematode population was evaluated in the soil and in the roots in seven moments: (i) fallow; (ii) pearl millet flowering; (iii) pearl millet maturity; (iv) maize flowering; (v) maize maturity; (vi) common bean flowering; and (vii) common bean maturity. The greatest control of the phytonematodes species described in the area was in the maize intercropped with crotalaria treatment, as the phytonematodes population decreased 2.49-fold in this treatment when compared to exclusive maize, resulting in an increase of 11.27% in common bean yield. Therefore, maize intercropped with crotalaria is a viable alternative to reduce phytonematodes infestation in common bean crop.

RESUMO A produção de feijão (Phaseolus vulgaris L.) pode ser prejudicada por diversas pragas e doenças, com destaque entre os patógenos de solo para os nematoides de galha, que causam perdas significativas. Objetivou-se avaliar a reação de genótipos de feijoeiro à reprodução desses nematoides, com ênfase nas duas espécies mais comumente encontradas parasitando a cultura: Meloidogyne javanica e Meloidogyne incognita. Os experimentos foram realizados em casa-de-vegetação, em delineamento inteiramente casualizado, com 26 tratamentos (genótipos), dez repetições e parcela composta por um vaso contendo uma planta. Cada parcela foi inoculada com 1.000 ovos e juvenis de segundo estádio e avaliada aos 62 dias após a inoculação, quando as populações finais foram estimadas. A resistência dos genótipos foi determinada com base em dois critérios: fator e índice de reprodução. Todos os genótipos foram suscetíveis a M. incognita por ambos os critérios. As cultivares IAC Alvorada, IAC Imperador, BRS Esplendor e BRS Esteio, embora possam ser classificadas como resistentes a M. javanica pelo fator de reprodução, são classificadas apenas como moderadamente resistentes se o critério de avaliação for o índice de reprodução.

ABSTRACT The production of common bean (Phaseolus vulgaris L.) may be compromised by a variety of pests and diseases, with root-knot nematodes standing out among the soil-borne pathogens that cause significant losses. It was assessed the reaction of common bean genotypes to the reproduction of these nematodes, with emphasis on the two species most frequently found parasitizing the crop: Meloidogyne javanica and Meloidogne incognita. The experiments were conducted in a greenhouse, using a completely randomized design, with 26 treatments (genotypes), ten replications and plot consisting of a pot containing one plant. Each plot was inoculated with 1,000 eggs and second-stage juveniles and assessed at 62 days after the inoculation, when the final populations were estimated. The genotypic resistance was determined based on two criteria: reproduction factor and index. All the genotypes were susceptible to M. incognita according to both assessment criteria. The IAC Alvorada, IAC Imperador, BRS Esplendor and BRS Esteio cultivars, although may be classified as resistant to M. javanica by the reproduction factor, are classified only as moderately resistant if the assessment criterion is the reproduction index.